This section provides background information related to the present disclosure which is not necessarily prior art.
Differential gears, also known as differentials, are used on drive axles in motor vehicles and serve primarily to transmit drive torque from a machine-driven gearbox output to a pair of ground-engaging wheels via a pair of axle half-shafts.
A differential gear is a special planetary gear, which in case of need, such as when the motor vehicle is cornering, ensures compensation for the different travel distances covered by the two wheels of the drive axle in that the wheels rotate at different speeds. Such a differential gear allows the wheels of an axle of a motor vehicle to turn at different rotational speeds.
For this, usually a differential cage is driven via a bevel gear or a spur pinion. The differential cage is connected to a crown wheel or a spur gear. Furthermore, a differential gear comprises at least two, usually however four, differential bevel gear wheels mounted rotatably on a bolt. The differential bevel gear wheels are not connected torque-transmissively together, but are connected torque-transmissively to a pair of axle bevel gear wheels. The axle bevel gear wheels are each fixedly connected to one of the axle half-shafts which, in turn, are each connected to one of the wheels.
The housing of a differential gear in the prior art is often designed in two pieces, amongst other reasons to increase the strength and facilitate installation, wherein the housing thus comprises a differential cage and a differential cover. The differential cage is connected to the (input) crown wheel. In the prior art, the connection of the two housing parts and the crown wheel is formed in widely varying ways. Furthermore, various forms of bolt fixing inside the differential housing are possible.
Document DE 10 2004 034 736 A1 describes for example a differential for a vehicle axle with a two-piece housing, in which the differential cage is welded to the differential cover and the crown wheel with only one radial weld seam. The differential cage is here configured such that it has a plurality of recesses on its periphery in the flange region of the crown wheel support. The differential cover has segments assigned to the recesses of the differential cage which engage in the recesses of the differential cage. Both the differential cage and the differential cover come together with the crown wheel, and the differential cage, differential cover and crown wheel can then be connected by only one radial weld seam.
The invention presented in document DE 10 2012 014 950 A1 concerns a housing for a differential gear of a motor vehicle, and a differential gear for a motor vehicle. The housing has a first housing part and a second housing part. Respective first parts of at least two receiver openings for respective bearing bolt parts are formed by the first housing part. Second parts of the receiver openings are formed by the second housing part. The housing parts are connected together, forming (complete) receiver openings. In the first separating plane of the housing, depending on the configuration of the receiver openings, a second separating plane is arranged, along which the receiver openings are divided in two. The housing parts are welded together in their first separating plane and where applicable in the second separating plane of the receiver openings. Protection against loss and/or twisting of the bearing bolt parts and/or differential gear wheels may be integrated in one of the housing parts. A 360° weld joint of the two housing parts is described for stronger connection thereof, wherein the receiver openings are structured such that the first halves and the second halves of the receiver openings each have a wall radially on the outside. In this way, a continuous circular weld seam is possible which allows a fixed mutual connection of the two housing parts.
While two-piece housings for differential gears are known and perform satisfactorily for their intended purpose, a need still exists to advance the art and provide alternative two-piece housing configurations for differential gears which optimize installation space requirements and are economical to produce.